Here on the east cost, and that includes any area east of the Rocky Mt's, monarch populations fly to their wintering areas in the mountains of Mexico. What causes this unusual behavior?
As the days grow shorter and the temperatures start to drop, this signals the orange and black butterflies that it is time to quite mating and laying eggs and start their journey to their winter roosting sites.
Millions of monarchs will make this journey in the fall feeding on the flowers as they go. In order to make it to their destination in time, they need to move quickly. Butterflies are cold-blooded insects so they are unable to fly when it gets cold.
Once they have arrived at their roosting spot they will be among millions of monarch butterflies that will literally cling to the trees for the entire winter. Because it is cold in Mexico, but not freezing, they kind of go into a "sleep" state. They move very little, so they don't need to be nourished during this time. In the spring, when Mexico's temperatures start to warm up, so do the monarch butterflies. They will start to scatter and look for food as they start their spring migration north.
The further north they fly, the more they will have eaten, and the more energy they will have. Eventually they will then mate, and the female will lay her eggs on the wild milkweed along the way. Those eggs will hatch after 3 - 5 days and the new caterpillars will eat the milkweed for about 14 days. At that point they will be mature caterpillars and will go through the last stage, which is the chrysalis. It takes just 10 days for the adult monarch to emerge for its' chrysalis shell. It will need about a day to gain its' strength so it can then continue its' parents flight to the area where its' parents originally left the previous fall.
What an accomplishment for such a small insect.
What can we do to help?
First, plant they type of nectar plants that butterflies like to drink from. Next, plant the host plants that they need to lay their eggs on. There are very specific plants that they must have to lay their eggs on. Each species of butterflies have 1 or 2 unique plants that they need. If they can't find their host plant, they won't lay any eggs. With urban sprawl happening even in our most rural areas, the butterflies are losing their nectar and host plants.
Last, but not least, we need to protect the wintering grounds for the monarch butterfly. The trees in the area where the monarchs go to roost are being cut down. The United States, Canada and Mexico need to work together to protect this area. We need to help Mexico preserve these areas. With out them, our Monarch populations will eventually disappear. For more information on what you can do to help, please visit Monarch Watch's website.